One of the most appealing options, particularly for millennials, would be #12 on your list (create a Blog/Youtube channel). The videos can be about anything that interests you, from your daily makeup routine (with affiliate links to the products you use), recipes (what you eat each day) or as you mention, instructional videos (again with affiliate links to the products you use). Once you gain a large following and viewership, you can earn via Adsense on YouTube.
The biggest surprise is real estate being second to last on my Passive Income Ranking List because I’ve written that real estate is my favorite investment class to build wealth. Physical real estate doesn’t stack up well against the other passive income sources due to the lack of liquidity and constant maintenance of tenants and property. The returns can be huge due to rising rental income AND principal over time, much like dividend investing. If you are a “proactive passive income earner” like myself, then real estate is great.
One of the easiest ways to get exposure to dividend stocks is to buy ETFs like DVY, VYM, and NOBL or index funds. You can also pay an algorithmic advisor like Wealthfront to automatically invest your money for you at a low fee. In the long run, it is very hard to outperform any index, therefore, the key is to pay the lowest fees possible while being invested in the market. Wealthfront charges $0 in fees for the first $15,000 and only 0.25% for any money over $10,000. Invest your idle money cheaply, instead of letting it lose purchasing power due to inflation. The key is to invest regularly.
What I did: I first identified my favorite places in the world to live: San Francisco, Honolulu, Paris, Amsterdam, New York City, and Lake Tahoe. I then looked up the median rent and housing prices for each city. Then I factored in private education costs for two kids to be conservative given I may not have two kids and public schools are often good enough. After calculating all vital costs, I then did a self-assessment of how happy I was making $50,000, $100,000, $150,000, $200,000, $250,000, $350,000, $500,000, and $750,000. I decided working 20 hours a week making $200,000 a year is the best income balance for maximum happiness. 
Case Schiller only tracks price appreciation of RE. RE as rental investment vehicle is measured primarily on rental yield or cap rate or some other measure. Price appreciation in that scenario is only a secondary means of growth, and arguably should be ignored as a predictor of returns when deciding on whether or not to invest in rentals. More important key performance indicators for rentals are net operating income and cash ROI. Appreciation, if it occurs, is a bonus.
I just wanted to say how nice it is to see such a positive exchange between strangers on the Internet. Seriously, not only was this article (list) motivating and well-drafted, the tiny little community of readers truly were a pleasant crescendo I found to be the cause of an inward smile. Thank you, everyone, and good luck to you all with your passive income efforts!! 🙂
In addition to an extra income stream, residual income allows you to diversify your revenue sources. Instead of relying on your standard paycheck, you’re earning money through the royalties of an eBook or the sales of an online course. Diversity of income gives your overall financial portfolio more security and depth. Similar to passive income, residual income gives you more financial stability, flexibility with your lifestyle, additional retirement savings, and a more robust financial standing.
In equity valuation, residual income represents an economic earnings stream and valuation method for estimating the intrinsic value of a company's common stock. The residual income valuation model values a company as the sum of book value and the present value of expected future residual income. Residual income attempts to measure economic profit, which is the profit remaining after the deduction of opportunity costs for all sources of capital.